In view of the increasing importance of polymers as substitutes for conventional materials of construction such as glass, metal, paper, and wood, the perceived need to conserve non-renewable resources such as petroleum and the dwindling amount of landfill capacity available for the disposal of waste products, considerable attention has been devoted in recent years to the problem of recovering, reclaiming, recycling or in some way reusing waste polymers.
It has also been proposed to pyrolyze or catalytically crack thermoplastic polymers so as to convert the high molecular weight polymer into volatile compounds having much lower molecular weight. The volatile compounds, depending on the process employed, may be either relatively high boiling liquid hydrocarbons useful as fuel oils or fuel oil supplements or light to medium boiling hydrocarbons useful as gasoline-type fuels or as chemical "building blocks". For example, polystyrene may be pyrolytically cracked so as to provide a substantial yield of styrene monomer.